Structure-based identification of pan-arenavirus sites of vulnerability

PROJECT SUMMARY Arenaviruses are enveloped RNA viruses with remarkably diverse Old World (OW) and New World (NW) serogroups that cause hemorrhagic fevers, for which there are currently limited treatment options. At present, ribavirin is the only off-label antiviral medication with efficacy against Lassa virus. The global prevalence, pandemic potential, probability for zoonotic transfer, and diversity of arenaviruses therefore justifies a sustained effort to identify and develop therapeutic countermeasures. Accelerated small molecule discovery, in addition to distinguishing novel inhibitors, may also provide essential mechanistic details of viral pathogenesis, revealing the molecular determinants of pan-reactivity of a diverse viral family. The arenavirus surface pre-glycoprotein polyprotein complex (GPC) and RNA polymerase (RNAP) complexes are two critical components of the viral cell entry and replication cycle. Given the overall similarity in molecular architecture and specific localized sequence conservation for each of these molecules across the large arenavirus family, they represent attractive targets for small molecule inhibitor identification. Recent structural information for prototypic OW and NW arenavirus GPCs and RNAPs has provided a foundation for identifying molecules that target structurally conserved, cross-reactive regions of these vital viral proteins. The proposed studies aim to fill a critical void in our understanding of pan- arenavirus sites of vulnerability through machine learning, artificial neural network molecular screening of small molecules against arenavirus GPCs (Aim 1) and RNAPs (Aim 2). Further characterization by in vitro structural, biochemical, and viral neutralization analysis of small molecule candidate inhibitors identified by the in silico screen will allow for inhibitor optimization for future animal challenge studies and combinatorial therapeutic development. By identifying GPC or polymerase-targeting molecules with broad, pan-arenavirus activity, we will define molecular specificities and commonalities of disparate arenavirus GPCs and polymerase complexes to guide immunogen design.